Tabuchi Norihiko, Kataoka-Ushijima Yoko, Talbert Alison, Mitani Harumi, Fukunaga Masahito
Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Japan.
Vector Borne Zoonotic Dis. 2008 Oct;8(5):607-13. doi: 10.1089/vbz.2007.0279.
We examined the vector competence of the tick, Ornithodoros moubata, using laboratory-reared gerbils as hosts. Transmission of the relapsing fever agent Borrelia duttonii occurred efficiently from infected ticks to uninfected gerbils and from infected gerbils to uninfected ticks. Spirochetes were maintained stably in the ticks for at least 3 months, but they disappeared from the bloodstream of infected gerbils after three episodes of spirochetemia. We also examined transovarial transmission of B. duttonii during the gonotrophic cycle and filial generation. No spirochetes could be detected from the offspring generation of the ticks by culture and polymerase chain reaction (PCR) methods, although spirochetes were still found in the female ticks. The results indicate that, because of the rarity of transovarial infection, the role of transovarial passage of B. duttonii to eggs and larval O. moubata ticks is limited in maintaining B. duttonii. Our findings strongly suggest that B. duttonii is maintained through the O. moubata tick-human transmission cycle in tick-borne relapsing fever endemic areas.
我们以实验室饲养的沙鼠作为宿主，检测了钝缘蜱（Ornithodoros moubata）的媒介能力。复发性发热病原体达顿疏螺旋体（Borrelia duttonii）能有效地从受感染的蜱传播至未受感染的沙鼠，也能从受感染的沙鼠传播至未受感染的蜱。螺旋体在蜱体内稳定存在至少3个月，但在受感染沙鼠经历三次螺旋体血症发作后，它们从沙鼠的血液中消失。我们还检测了达顿疏螺旋体在蜱的生殖营养周期和子代中的经卵传播情况。尽管在雌性蜱中仍能发现螺旋体，但通过培养和聚合酶链反应（PCR）方法，在蜱的子代中未检测到螺旋体。结果表明，由于经卵感染的情况罕见，达顿疏螺旋体经卵传递至卵和幼蜱在维持达顿疏螺旋体方面的作用有限。我们的研究结果强烈表明，在蜱传复发性发热流行地区，达顿疏螺旋体是通过钝缘蜱-人传播循环得以维持的。
